[kbuild-all] [linux-next:master 1527/2770] drivers/char/pcmcia/cm4000_cs.c:569:16: warning: iteration 4 invokes undefined behavior

tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: ec2618180c3450d06a6a4ba951d4c9a2c689b517 commit: 5ae6eadfdaf431f47adbdf1754f3b5a5fd638de2 [1527/2770] asm-generic/io.h: warn in inb() and friends with undefined PCI_IOBASE config: m68k-randconfig-r035-20210513 (attached as .config) compiler: m68k-linux-gcc (GCC) 9.3.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commi... git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout 5ae6eadfdaf431f47adbdf1754f3b5a5fd638de2 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross W=1 ARCH=m68k If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): drivers/char/pcmcia/cm4000_cs.c: In function 'cmm_write': drivers/char/pcmcia/cm4000_cs.c:1053:16: warning: variable 'tmp' set but not used [-Wunused-but-set-variable] 1053 | unsigned char tmp; | ^~~ drivers/char/pcmcia/cm4000_cs.c: In function 'set_protocol': 569 | pts_reply[i] = inb(REG_BUF_DATA(iobase)); | ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/char/pcmcia/cm4000_cs.c:567:2: note: within this loop 567 | for (i = 0; i < num_bytes_read; i++) { | ^~~ vim +569 drivers/char/pcmcia/cm4000_cs.c c1986ee9bea3d8 Harald Welte 2005-11-13 516 c1986ee9bea3d8 Harald Welte 2005-11-13 517 /* set number of bytes to write */ c1986ee9bea3d8 Harald Welte 2005-11-13 518 DEBUGP(5, dev, "Set number of bytes to write\n"); c1986ee9bea3d8 Harald Welte 2005-11-13 519 xoutb(0x04, REG_NUM_SEND(iobase)); c1986ee9bea3d8 Harald Welte 2005-11-13 520 c1986ee9bea3d8 Harald Welte 2005-11-13 521 /* Trigger CARDMAN CONTROLLER */ c1986ee9bea3d8 Harald Welte 2005-11-13 522 xoutb(0x50, REG_FLAGS0(iobase)); c1986ee9bea3d8 Harald Welte 2005-11-13 523 c1986ee9bea3d8 Harald Welte 2005-11-13 524 /* Monitor progress */ c1986ee9bea3d8 Harald Welte 2005-11-13 525 /* wait for xmit done */ c1986ee9bea3d8 Harald Welte 2005-11-13 526 DEBUGP(5, dev, "Waiting for NumRecBytes getting valid\n"); c1986ee9bea3d8 Harald Welte 2005-11-13 527 c1986ee9bea3d8 Harald Welte 2005-11-13 528 for (i = 0; i < 100; i++) { c1986ee9bea3d8 Harald Welte 2005-11-13 529 if (inb(REG_FLAGS0(iobase)) & 0x08) { c1986ee9bea3d8 Harald Welte 2005-11-13 530 DEBUGP(5, dev, "NumRecBytes is valid\n"); c1986ee9bea3d8 Harald Welte 2005-11-13 531 break; c1986ee9bea3d8 Harald Welte 2005-11-13 532 } be826ada52f1fc Jia-Ju Bai 2018-03-18 533 usleep_range(10000, 11000); c1986ee9bea3d8 Harald Welte 2005-11-13 534 } c1986ee9bea3d8 Harald Welte 2005-11-13 535 if (i == 100) { c1986ee9bea3d8 Harald Welte 2005-11-13 536 DEBUGP(5, dev, "Timeout waiting for NumRecBytes getting " c1986ee9bea3d8 Harald Welte 2005-11-13 537 "valid\n"); c1986ee9bea3d8 Harald Welte 2005-11-13 538 rc = -EIO; c1986ee9bea3d8 Harald Welte 2005-11-13 539 goto exit_setprotocol; c1986ee9bea3d8 Harald Welte 2005-11-13 540 } c1986ee9bea3d8 Harald Welte 2005-11-13 541 c1986ee9bea3d8 Harald Welte 2005-11-13 542 DEBUGP(5, dev, "Reading NumRecBytes\n"); c1986ee9bea3d8 Harald Welte 2005-11-13 543 for (i = 0; i < 100; i++) { c1986ee9bea3d8 Harald Welte 2005-11-13 544 io_read_num_rec_bytes(iobase, &num_bytes_read); c1986ee9bea3d8 Harald Welte 2005-11-13 545 if (num_bytes_read >= 4) { c1986ee9bea3d8 Harald Welte 2005-11-13 546 DEBUGP(2, dev, "NumRecBytes = %i\n", num_bytes_read); c1986ee9bea3d8 Harald Welte 2005-11-13 547 break; c1986ee9bea3d8 Harald Welte 2005-11-13 548 } be826ada52f1fc Jia-Ju Bai 2018-03-18 549 usleep_range(10000, 11000); c1986ee9bea3d8 Harald Welte 2005-11-13 550 } c1986ee9bea3d8 Harald Welte 2005-11-13 551 c1986ee9bea3d8 Harald Welte 2005-11-13 552 /* check whether it is a short PTS reply? */ c1986ee9bea3d8 Harald Welte 2005-11-13 553 if (num_bytes_read == 3) c1986ee9bea3d8 Harald Welte 2005-11-13 554 i = 0; c1986ee9bea3d8 Harald Welte 2005-11-13 555 c1986ee9bea3d8 Harald Welte 2005-11-13 556 if (i == 100) { c1986ee9bea3d8 Harald Welte 2005-11-13 557 DEBUGP(5, dev, "Timeout reading num_bytes_read\n"); c1986ee9bea3d8 Harald Welte 2005-11-13 558 rc = -EIO; c1986ee9bea3d8 Harald Welte 2005-11-13 559 goto exit_setprotocol; c1986ee9bea3d8 Harald Welte 2005-11-13 560 } c1986ee9bea3d8 Harald Welte 2005-11-13 561 c1986ee9bea3d8 Harald Welte 2005-11-13 562 DEBUGP(5, dev, "Reset the CARDMAN CONTROLLER\n"); c1986ee9bea3d8 Harald Welte 2005-11-13 563 xoutb(0x80, REG_FLAGS0(iobase)); c1986ee9bea3d8 Harald Welte 2005-11-13 564 c1986ee9bea3d8 Harald Welte 2005-11-13 565 /* Read PPS reply */ c1986ee9bea3d8 Harald Welte 2005-11-13 566 DEBUGP(5, dev, "Read PPS reply\n"); c1986ee9bea3d8 Harald Welte 2005-11-13 567 for (i = 0; i < num_bytes_read; i++) { c1986ee9bea3d8 Harald Welte 2005-11-13 568 xoutb(i, REG_BUF_ADDR(iobase)); c1986ee9bea3d8 Harald Welte 2005-11-13 @569 pts_reply[i] = inb(REG_BUF_DATA(iobase)); c1986ee9bea3d8 Harald Welte 2005-11-13 570 } c1986ee9bea3d8 Harald Welte 2005-11-13 571 :::::: The code at line 569 was first introduced by commit :::::: c1986ee9bea3d880bcf0d3f1a31e055778f306c7 [PATCH] New Omnikey Cardman 4000 driver :::::: TO: Harald Welte <laforge(a)gnumonks.org&gt; :::::: CC: Linus Torvalds <torvalds(a)g5.osdl.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org